---
type: reference
title: Media Metadata View
description: "The SSD-backed overlay the two media servers read and write: shape, guards, commands, laws, rollback."
tags: [dankserver, media-server, jellyfin, plex, storage]
timestamp: 2026-10-30T00:00:00Z
---

# Media Metadata View

`/mnt/media` is an OverlayFS merge of the media library: the RAID6 array below,
a directory on the NVMe above. It exists so [[Jellyfin]] can write Kodi-format
sidecars (`movie.nfo`, `tvshow.nfo`, `episode.nfo`, artwork) that [[Plex]] can
read. Sidecar metadata is only useful sitting next to the media file, and the
array is read-only and slow — so the bytes stay there and the *writes* land on
SSD. One tree to both servers, one copy of the media.

## Shape

| Item | Value |
|---|---|
| Lower layer | `/mnt/entropy` — the RAID6 array, source of truth, never written |
| Upper layer | `/var/lib/media-meta/upper` — NVMe; every write lands here |
| Work dir | `/var/lib/media-meta/work` — overlayfs internals, same filesystem |
| Mount point | `/mnt/media`, unit `mnt-media.mount` (`WantedBy=local-fs.target`) |
| Repo source | `dankserver/host/systemd/mnt-media.mount` — host copy is generated state |
| Installer | `scripts/media-view.sh` — `plan` / `install` / `verify` / `status` / `reap` |
| Written by | Jellyfin only (Plex binds read-only); nothing else in the fleet touches it |

Both consumers guard the view with
`UnitConfigItem=ConditionPathIsMountPoint=/mnt/media`, and `scripts/deploy.sh
dankserver --service jellyfin|plex` calls `media-view.sh install` + `verify`
before it restarts either container.

| Consumer | Bind | Mode | Why that path |
|---|---|---|---|
| [[Jellyfin]] | `/mnt/media:/data` | rw | It is the metadata writer; its sidecars become SSD bytes |
| [[Plex]] | `/mnt/media:/mnt/entropy` | ro | Every path in the PMS database was recorded as `/mnt/entropy/...`; only the HOST side of the bind moved, so its database still resolves |

Putting the sidecars inside Plex's reach is not the same as making Plex use them:
a library parses `.nfo` only with its *Local media information* agent enabled, and
this change touches no library setting.

## Commands

```bash
scripts/media-view.sh plan              # print the resolved shape, touch nothing
sudo scripts/media-view.sh install      # create dirs, install the unit, mount, enable
scripts/media-view.sh verify            # is /mnt/media really the overlay? (deploy gate)
scripts/media-view.sh status            # mount options + upper-layer size/file count
scripts/media-view.sh reap              # list ghost metadata (media moved, sidecars left)
sudo scripts/media-view.sh reap --apply # move ghosts to the SSD trash, never delete
```

`--upper-base DIR` and `--lower DIR` relocate the layers; the defaults are the
host values above.

## Laws

- **The upper layer must sit on non-rotational storage.** `install` and `verify`
  refuse via `lsblk -dno ROTA` if the upper base lives on the array: an overlay
  whose upper is the spinners is the original problem with extra steps, and it
  silently turns every metadata write back into a seek.
- **Never mount the view over an unmounted lower.** `RequiresMountsFor=/mnt/entropy`
  plus the container `ConditionPathIsMountPoint` guards: an empty `lowerdir`
  presents an *empty library* as truth, and a media scan would then clear the
  database of everything.
- **Never delete through `/mnt/media`.** A delete writes an overlayfs whiteout
  (`.wh.<name>`) in the upper layer, which hides the array's copy without
  removing it — the file reappears the moment the view is unmounted, and the
  upper layer now carries a landmine. Deletions belong on the raw path
  (`/mnt/entropy`), which the relayout tool already treats as the only writer.
  `reap` refuses to remove whiteouts and only warns about them.
- **A relayout must be followed by `reap`.** Renames happen on the raw path, so
  sidecars the view already wrote stay at the old coordinates: a ghost folder
  the servers browse and find nothing in. `reap` lists upper-layer directories
  with no counterpart below and moves them (with their subtree) into a dated
  `.AGENTTRASH/` under the SSD base. It is recursive and file-safe: a sidecar
  that exists only above is normal, so only *directories* are candidates.
- **File-watcher events do not cross the overlay.** Plex's NFO agent and
  Jellyfin's real-time monitor see inotify events for writes that land *in the
  upper layer*, not for changes on the array underneath. After any relayout or
  externally-written metadata, trigger a library refresh — see
  [[Media Relayout]] for the refresh procedure.

## Failure signatures

| Symptom | Meaning |
|---|---|
| `jellyfin.service` / `plex.service` show `ConditionPathIsMountPoint=... was not met` and stay inactive | `/mnt/media` is not mounted. Do not start them anyway: `scripts/media-view.sh install`, then `verify`. |
| Jellyfin log: `Read-only file system : '/data/Movies/…/movie.nfo'` | The container is binding the raw array, not the view — the quadlet drifted back or the view is gone. `media-view.sh status`. |
| A folder appears in a media server with artwork/`.nfo` but no video | Ghost metadata from a relayout. `media-view.sh reap`. |
| `verify` prints `refused: /mnt/media is not a mountpoint` | Someone made a plain directory there. That is the fail-closed guard working; remove it and install. |

## Rollback

Revert the commit that pointed the two quadlets at the view and re-deploy both
services — they bind `/mnt/entropy` read-only again, which is the pre-view
shape. The NVMe upper layer can stay: nothing reads it once the binds are back,
and it holds no state either server needs. Removing the mount alone
(`systemctl stop mnt-media.mount`) is safe while no container binds it, and the
array is never modified by any of this.

## Links

- [[Jellyfin]] — the metadata writer; its data layout section.
- [[Plex]] — the read-only consumer; in-place bind-mount history.
- [[Media Relayout]] — the tool that moves media on the raw path and the reason `reap` exists.
- [[Entropy Volume]] — the array underneath.